Big Dippers – Noctural Dipping and CV

There exist a normal physiologic variation in blood pressure and the wake-sleep cycle. There should be a normal decrease of approximately 20% in BP during sleep due to a decrease in sympathetic activity. Conversely there is an increase in BP just before waking and this is believed to be associated with an increase incidence of myocardial infarctions, stroke, and sudden death. This normally is seen between 6AM and 10AM.

There are a number of patients that don’t “dip.” This could be due to medications, poor sleep, or advanced kidney disease.  Several studies have shown that antihypertensives could be use to convert these “non-dippers” to “dippers” and ultimately decrease there cardiovascular events. There is currently a RCT being planned to further determine if night-time doses of non-diuretic anti-hypertensives reduces CV risk compared with traditional AM dosing (diuretics aren’t recommended for PM dosing because patients are out of bed urinating more at night and aren’t actually experience the “dip.” Interestingly short or intermediate-acting ACE inhibitors/ARBs and CCB were found to have a greater advantage in converting non-dippers. Longer acting ACE inhibitors (such as fosinopril) and CCB (such as amlodipine) had a smaller effect.
– Adrian
References

1. Carter BL, Chrischilles EA, Rosenthal G, Gryzlak BM, Eisenstein EL, Vander Weg MW. Efficacy and safety of nighttime dosing of antihypertensives: review of the literature and design of a pragmatic clinical trial. J Clin Hypertens (Greenwich). 2014;16:115-121.
2. Roush GC, Fapohunda J, Kostis JB. Evening dosing of antihypertensive therapy to reduce cardiovascular events: a third type of evidence based on a systematic review and meta-analysis of randomized trials. J Clin Hypertens (Greenwich). 2014;16:561-568.
3. Goswami P, Drawz P, Rahman M. Nocturnal dosing and chronic kidney disease progression: new insights. Curr Opin Nephrol Hypertens. 2009;18:381-385.
4. Comprehensive Clinical Nephrology 4th Edition. Elseiver 2010.